The present invention relates to a method and device for exciting a three-layer structure thin-film EL display panel exhibiting the hysteresis loop phenomenon in the applied voltage versus brightness characteristics, and more particularly to a method for executing light-activated register and erasure on the thin-film EL display panel.
As discussed in U.S. Pat. No. 3,975,661 DRIVING METHOD FOR A THIN-FILM ELECTROLUMINESCENT ELEMENT OF A THREE-LAYER CONSTRUCTION assigned to the same assignee as this application, it was revealed that the three-layer structure thin-film EL display panel including a thin-film layer of electroluminescent material doped with active material serving as luminous centers, for example, ZnS:Mn sandwiched by a pair of dielectric layers such as Y.sub.2 O.sub.3, exhibited the hysteresis loop phenomenon in the applied voltage versus brightness characteristics. Utilization of such hysteresis loop characteristics makes it possible to operate the EL display panel as a sort of memory function element and it is therefore free to write, sustain and erase any intelligence signal as a function of brightness of the EL element.
It is therefore an object of the present invention to provide an improvement in a circuit arrangement for driving the above described three-layer structure thin-film EL display panel. The present invention features a light-excited intelligence write mode and a light-excited intelligence erase mode.